From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF99F31195D for ; Wed, 11 Feb 2026 15:43:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770824596; cv=none; b=HgfzOyk0zA0PcF1u5UkB0bGQoTsaaB9NOo+Xov5PdZ+Q5JP+Y15dVd82X1l2h0l8gfSyDce4EcmGBHqw2lgyj7FsSc56nESeHMK4yxzS47bpFW/2ZhvJvcYZYCCMDyvDctUw/od36ysK8imTJllAYZPUz43ZUKzUQzfEfjODYzI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770824596; c=relaxed/simple; bh=cx5p1N0pxNkNyb36JTGId6j7cNzPbI2HBY0TDNnjvyo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GgwLvnlekmKL1Zfqsirf8U4HHKjVbt/xnMHpcc7kTSe7ZMSDJs6uuI0biH2Inc0OOiccjmYvUy9zKx69VWnJ62sb31M707odjBDTErP06DLix0D/gaXOncLjxjbp50U4tgWImwI5f1Js1UikYIYHzh52Z9ZqfXuK3mAlcqbPLVk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=gKVu/p8g; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gKVu/p8g" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770824593; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1jx1hsuuG7ObMhO/uK+TRbv/qG1QFFvi3Ae/jdkXmec=; b=gKVu/p8gLhfHc6dtBBwuIWU4BjNVSkuxtzgWPdqb1SxDmfaDxUF8BhRLXGYhrlb22a6inO iwLMMdb3tFG0gwcah1v7fqXPFyEN1mynogooHsVTFiqosH0BBX8ZPOjfVcfB4tImgUWlY3 7gYgyfNvt12WKIwSJiQ7JWIzljbt1pM= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-121-hUcKwGwXPeOaG_WdkWuOAw-1; Wed, 11 Feb 2026 10:43:06 -0500 X-MC-Unique: hUcKwGwXPeOaG_WdkWuOAw-1 X-Mimecast-MFC-AGG-ID: hUcKwGwXPeOaG_WdkWuOAw_1770824584 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DCECD1800370; Wed, 11 Feb 2026 15:43:03 +0000 (UTC) Received: from tpad.localdomain (unknown [10.96.133.3]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 057AA30002D5; Wed, 11 Feb 2026 15:43:02 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 492B8400DF78C; Wed, 11 Feb 2026 09:09:02 -0300 (-03) Date: Wed, 11 Feb 2026 09:09:02 -0300 From: Marcelo Tosatti To: Leonardo Bras Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Leonardo Bras , Thomas Gleixner , Waiman Long , Boqun Feng Subject: Re: [PATCH 1/4] Introducing qpw_lock() and per-cpu queue & flush work Message-ID: References: <20260206143430.021026873@redhat.com> <20260206143741.525190180@redhat.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Hi Leonardo, On Fri, Feb 06, 2026 at 09:16:36PM -0300, Leonardo Bras wrote: > > =================================================================== > > --- slab.orig/MAINTAINERS > > +++ slab/MAINTAINERS > > @@ -21291,6 +21291,12 @@ F: Documentation/networking/device_drive > > F: drivers/bus/fsl-mc/ > > F: include/uapi/linux/fsl_mc.h > > > > +QPW > > +M: Leonardo Bras > > Thanks for keeping that up :) > Could you please change this line to > > +M: Leonardo Bras > > As I don't have access to Red Hat's mail anymore. > The signoffs on each commit should be fine to keep :) Done. > > > +S: Supported > > +F: include/linux/qpw.h > > +F: kernel/qpw.c > > + > > Should we also add the Documentation file as well? > > +F: Documentation/locking/qpwlocks.rst Done. > > +The queue work related functions (analogous to queue_work_on and flush_work) are: > > +queue_percpu_work_on and flush_percpu_work. > > + > > +The behaviour of the QPW functions is as follows: > > + > > +* !CONFIG_PREEMPT_RT and !CONFIG_QPW (or CONFIG_QPW and qpw=off kernel > > I don't think PREEMPT_RT is needed here (maybe it was copied from the > previous QPW version which was dependent on PREEMPT_RT?) Ah, OK, my bad. Well, shouldnt CONFIG_PREEMPT_RT select CONFIG_QPW and CONFIG_QPW_DEFAULT=y ? > > +boot parameter): > > + - qpw_lock: local_lock > > + - qpw_lock_irqsave: local_lock_irqsave > > + - qpw_trylock: local_trylock > > + - qpw_trylock_irqsave: local_trylock_irqsave > > + - qpw_unlock: local_unlock > > + - queue_percpu_work_on: queue_work_on > > + - flush_percpu_work: flush_work > > + > > +* CONFIG_PREEMPT_RT or CONFIG_QPW (and CONFIG_QPW_DEFAULT or qpw=on kernel > > Same here > > > +boot parameter), > > + - qpw_lock: spin_lock > > + - qpw_lock_irqsave: spin_lock_irqsave > > + - qpw_trylock: spin_trylock > > + - qpw_trylock_irqsave: spin_trylock_irqsave > > + - qpw_unlock: spin_unlock > > + - queue_percpu_work_on: executes work function on caller cpu > > + - flush_percpu_work: empty > > + > > +qpw_get_cpu(work_struct), to be called from within qpw work function, > > +returns the target cpu. > > > > > > > Other than that, LGTM! > > Reviewed-by: Leonardo Bras > > Thanks! > Leo > >